Your goal is keep the jelly monsters under the borderline by tapping on 2 or more adjacent monsters of the same type.
Be quick as every X seconds new monsters arrive from top.
You also have 3 powers to help you maintain the monsters:
The Bomb - helps with adjacent monsters
The Laser - helps with vertical and horizontal monsters
The Lightning - helps with monsters of that type
Tapping on large groups of monsters of the same type earns you greater points.
You can manually call more monsters by tapping on the timer.
Compete with your friends and make the highest score.
Have fun.